This invention relates to the method and apparatus of electroplating metal parts such as, for example, U-shaped metal frames commonly used to support the adjustable headrests in an automobile or other motor vehicle. Examples of different methods and apparatus for electroplating parts are disclosed in U.S. Pat. Nos. 4,184,927, 5,788,829, 6,090,260, 7,807,027 and 7,850,830. In the electroplating of metal parts, it is common to use a rack plating system or a barrel plating system. In the rack system, multiple racks hang from or depend from some form of gantry system or conveyor, and multiple parts are usually supported by each rack. The racks with the supported parts are progressively moved by the conveyor through the plating process, and the racks and parts are successfully dipped into each plating solution. However, it is difficult to control the plating thickness on each part, with the result that there is usually a large variation of plating thickness on the part. DC current for plating is supplied from a rectifier to the parts through the gantry or conveyor system. When there is an accident or problem on the plating line, it is frequently necessary to remove all of the racks and parts from the conveyor, which may result in hours of down time of the plating line.
In barrel type electroplating, commonly the parts are placed into a barrel which is suspended from a gantry or conveyor, and the barrel takes the parts through the plating process by lowering the barrel into each plating solution while the barrel is rotated in the solution for a predetermined time. While the barrel plating system usually provides a more uniform plating thickness on the parts than does rack plated parts, there is no way to control the plating on one part from another part in the barrel.